To establish if there are reduced levels of damage in the HSC compartment after N-acetylcysteine treatment, we administered 1mg/mL of NAC in the drinking water to young and aged C57BL/6 male mice. Age-matched non-treated control cohorts were also included in the experiment. Initial FLARE comet experiments assaying for DNA damage demonstrated a significant decrease in the levels of oxidative damage (FPG+) in old HSCs after one month of NAC treatment. We examined the bone marrow for changes in the primitive bone marrow compartments, but do not see any significant differences in the primitive bone marrow compartments assayed. Functional assays of NAC treated HSCs by transplant assays demonstrated no significant changes in functional potential of HSCs with reduced oxidative damage in peripheral blood (Old-NAC vs Old-WT) or in bone marrow analysis in the primary transplant. To test long term potential of HSCs, secondary transplants were performed on 200 donor derived HSCs again 2x105 congenic competitor cells. Peripheral blood analysis again showed no significant differences in either total reconstitution or in lineage composition four months post-secondary transplant. Current efforts are focused on establishing if aged HSC function can be improved by supplementing NAC during the transplant setting, where the HSCs will be actively dividing, and antioxidant benefits may be more pronounced in this setting.